如何在Tomcat 9.0.0M10中修复“已扫描但未发现TLD的罐子”

Question

我是Java EE的新手，尝试使用ServletContextListener，监听器作业是连接到数据库bla bla。当我尝试启动服务器(Tomcat9)，它卡在：

“信息：已扫描至少一个JAR以查找TLD，但未包含TLD。请为此记录器启用调试日志记录，以获取已扫描但未在其中找到TLD的JAR的完整列表。在扫描期间跳过不需要的JAR可以改善启动时间和JSP编译时间。”

于是我把“日志属性文件”中的一些属性改成这样：

    # Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

handlers = 1catalina.org.apache.juli.AsyncFileHandler, 2localhost.org.apache.juli.AsyncFileHandler, 3manager.org.apache.juli.AsyncFileHandler, 4host-manager.org.apache.juli.AsyncFileHandler, java.util.logging.ConsoleHandler

.handlers = 1catalina.org.apache.juli.AsyncFileHandler, java.util.logging.ConsoleHandler

############################################################
# Handler specific properties.
# Describes specific configuration info for Handlers.
############################################################

1catalina.org.apache.juli.AsyncFileHandler.level = FINE
1catalina.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
1catalina.org.apache.juli.AsyncFileHandler.prefix = catalina.

2localhost.org.apache.juli.AsyncFileHandler.level = FINE
2localhost.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
2localhost.org.apache.juli.AsyncFileHandler.prefix = localhost.

3manager.org.apache.juli.AsyncFileHandler.level = FINE
3manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
3manager.org.apache.juli.AsyncFileHandler.prefix = manager.

4host-manager.org.apache.juli.AsyncFileHandler.level = FINE
4host-manager.org.apache.juli.AsyncFileHandler.directory = ${catalina.base}/logs
4host-manager.org.apache.juli.AsyncFileHandler.prefix = host-manager.

java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = org.apache.juli.OneLineFormatter


############################################################
# Facility specific properties.
# Provides extra control for each logger.
############################################################

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = 2localhost.org.apache.juli.AsyncFileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].handlers = 3manager.org.apache.juli.AsyncFileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].level = FINE
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].handlers = 4host-manager.org.apache.juli.AsyncFileHandler

# For example, set the org.apache.catalina.util.LifecycleBase logger to log
# each component that extends LifecycleBase changing state:
#org.apache.catalina.util.LifecycleBase.level = FINE

# To see debug messages in TldLocationsCache, uncomment the following line:
org.apache.jasper.compiler.TldLocationsCache.level = FINE
org.apache.jasper.servlet.TldScanner.level = FINE

# To see debug messages for HTTP/2 handling, uncomment the following line:
#org.apache.coyote.http2.level = FINE

# To see debug messages for WebSocket handling, uncomment the following line:
#org.apache.tomcat.websocket.level = FINE

所有答案都可以接受。谢谢你们。

Answer 1

将日志设置为FINE、FINEST或ALL以查找要排除的所有JAR不是必需的。

下面是一个脚本，它查找所有不包含TLDs的JAR（更改TOMCAT_HOME变量以匹配您的安装），并在表单上输出一个列表

jar1.jar,\
jar2.jar,\
...

可以粘贴到catalina.properties中（省略最后一个“,\”）：

#!/bin/sh
TOMCAT_HOME=/opt/tomcat
for i in `find $TOMCAT_HOME -follow -name "*jar"`
do
    jar tvf $i | grep -i tld > /dev/null
    if [ $? -ne 0 ]; then
        echo "$(basename $i),\\"
    fi
done

但是，如果我得到了正确的通知，Tomcat9中有可能通过更改（在catalina.properties中）来排除所有JAR：

tomcat.util.scan.StandardJarScanFilter.jarsToSkip=\

至

tomcat.util.scan.StandardJarScanFilter.jarsToSkip=*.jar

（注释掉下面几行中的列表），然后通过更改：

tomcat.util.scan.StandardJarScanFilter.jarsToScan=\
log4j-web*.jar,log4j-taglib*.jar,log4javascript*.jar,slf4j-taglib*.jar

并添加通过修改上面的脚本获得的列表，以列出确实包含TLDS的JAR：

#!/bin/sh
TOMCAT_HOME=/opt/tomcat
for i in `find $TOMCAT_HOME -follow -name "*jar"`
do
    jar tvf $i | grep -i tld > /dev/null
    if [ $? -eq 0 ]; then
        echo "$(basename $i),\\"
    fi
done

Answer 2

这不是Tomcat中的bug或任何类型的问题。Tomcat只是通知您，有些JAR不包含TLD，您可以将它们添加到扫描器的跳过列表中，以提高启动性能。因此您有两种选择：

>

您可以安全地忽略该提示。但是，如果您感到恼火，您可以将特定日志记录程序设置为更高的日志记录级别，从而阻止tomcat对其进行日志记录。只需将org.apache.jasper.servlet.tldscanner.level=severe添加到logging.properties的末尾。

启用调试日志，使tomcat列出这些JAR，并将它们添加到跳过列表中。设置：

org.apache.jasper.compiler.TldLocationsCache.level = FINE
org.apache.jasper.servlet.TldScanner.level = FINE

并将打印的JAR名称（不带路径）添加到tomcat_dir/conf/catalina.properties中的tomcat.util.scan.standardJarScanFilter.jarstoskip=...中